Interchangeable lens and method for controlling the same, shooting apparatus, and camera system

ABSTRACT

The present technology relates to an interchangeable lens and a method for controlling the same capable of starting shooting in consideration of mechanical fluctuations after a diaphragm is driven, a shooting apparatus, and a camera system. An interchangeable lens includes: a diaphragm; a diaphragm driving unit configured to drive the diaphragm; and a lens control unit configured to transmit diaphragm driving information including stabilization time information of the diaphragm to a shooting apparatus when the diaphragm driving unit drives the diaphragm. The present technology is applicable to lens-interchangeable digital cameras, and the like, for example.

TECHNICAL FIELD

The present technology relates to an interchangeable lens and a methodfor controlling the same, a shooting apparatus, and a camera system, andparticularly to an interchangeable lens and a method for controlling thesame capable of starting shooting in consideration of mechanicalfluctuations after a diaphragm is driven, a shooting apparatus, and acamera system.

BACKGROUND ART

A diaphragm of a shooting apparatus is configured of seven blades andthe like, for example, and increases or decreases the aperture diameterthereby to adjust the amount of light passing through an optical system.The blades of the diaphragm are generally driven by a motor via a gear,a shaft, or the like. There is known a shooting apparatus configured tostart shooting after a diaphragm finishes being adjusted.

CITATION LIST Patent Document

Patent Document 1: Japanese Patent Application Laid-Open No. 2010-2900

SUMMARY OF THE INVENTION Problems to be Solved by the Invention

A change in aperture diameter of a diaphragm is influenced by loosebetween gears, twist of a shaft, or the like, and the aperture diameterconverges on a target size while being subjected to overshoot orundershoot, for example, relative to the target size after a motorfinishes being driven. It is not possible to know a time until overshootor undershoot ends, and thus shooting can be started while a mechanicaloperation of the diaphragm does not end, for example.

The present technology has been made in terms of such a situation, andis directed to enabling shooting to be started in consideration ofmechanical fluctuations after a diaphragm is driven.

Solutions to Problems

An interchangeable lens according to a first aspect of the presenttechnology includes: a diaphragm; a diaphragm driving unit configured todrive the diaphragm; and a lens control unit configured to transmitdiaphragm driving information including stabilization time informationof the diaphragm to a shooting apparatus when the diaphragm driving unitdrives the diaphragm.

In an interchangeable lens control method according to the first aspectof the present technology, a lens control unit of an interchangeablelens including a diaphragm, a diaphragm driving unit configured to drivethe diaphragm, and the lens control unit transmits diaphragm drivinginformation including stabilization time information of the diaphragm tothe shooting apparatus when the diaphragm driving unit drives thediaphragm.

According to the first aspect of the present technology, the diaphragmdriving information including the stabilization time information of thediaphragm is transmitted to the shooting apparatus when the diaphragmdriving unit drives the diaphragm.

A shooting apparatus according to a second aspect of the presenttechnology includes a body control unit configured to determine anexposure start timing on the basis of diaphragm driving informationincluding stabilization time information of a diaphragm acquired from aninterchangeable lens.

According to the second aspect of the present technology, the exposurestart timing is determined on the basis of the diaphragm drivinginformation including the stabilization time information of thediaphragm acquired from the interchangeable lens.

A camera system according to a third aspect of the present technologyincludes an interchangeable lens and a shooting apparatus on which theinterchangeable lens is mounted, in which the interchangeable lensincludes: a diaphragm; a diaphragm driving unit configured to drive thediaphragm; and a lens control unit configured to transmit diaphragmdriving information including stabilization time information of thediaphragm to the shooting apparatus when the diaphragm driving unitdrives the diaphragm, and the shooting apparatus includes: a bodycontrol unit configured to determine an exposure start timing on thebasis of the diaphragm driving information.

According to the third aspect of the present technology, theinterchangeable lens transmits the diaphragm driving informationincluding the stabilization time information of the diaphragm when thediaphragm driving unit drives the diaphragm to the shooting apparatus,and the shooting apparatus determines the exposure start timing on thebasis of the diaphragm driving information.

Effects of the Invention

According to the first to third aspects of the present technology, it ispossible to start shooting in consideration of mechanical fluctuationsafter the diaphragm is driven.

Additionally, the effects described herein are not necessarilyrestrictive, and any effect described in the present disclosure may beobtained.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a block diagram illustrating an exemplary configuration of oneembodiment of a camera system according to the present technology.

FIG. 2 is a diagram for explaining the operations of a diaphragm whenthe aperture diameter of the diaphragm is changed.

FIG. 3 is a time chart for explaining a shooting processing.

FIG. 4 is a diagram for explaining how to calculate a diaphragm drivingend time by a lens control unit.

FIG. 5 is a diagram illustrating exemplary table data stored in arecording unit.

FIG. 6 is a diagram illustrating still other exemplary table data storedin the recording unit.

FIG. 7 is a flowchart for explaining the processings performed in aninterchangeable lens and a body.

FIG. 8 is a flowchart for explaining the processings of acquiring adiaphragm driving parameter.

FIG. 9 is a flowchart for explaining the processings performed in theinterchangeable lens and the body.

FIG. 10 is an exploded view of a first light amount adjustment apparatusfor explaining a cause of overshoot.

FIG. 11 is an exploded view of a second light amount adjustmentapparatus for explaining a cause of overshoot.

FIG. 12 is an exploded view of a third light amount adjustment apparatusfor explaining a cause of overshoot.

FIG. 13 is a flowchart for explaining a command transmission controlprocessing.

FIG. 14 is a time chart illustrating exemplary packet communication madein step S104 of FIG. 13.

FIG. 15 is a time chart illustrating exemplary packet communication madein step S105 of FIG. 13.

FIG. 16 is a time chart illustrating exemplary packet communication madein step S107 of FIG. 13.

MODE FOR CARRYING OUT THE INVENTION

Modes (denoted as embodiments below) for carrying out the presenttechnology will be described below. Additionally, the description willbe made in the following order.

1. Block diagram of camera system2. Operations of diaphragm3. Time chart of shooting processing4. How to calculate diaphragm driving end time

5. Flowchart

6. Exemplary processings when diaphragm driving end time is calculate inbody7. Exemplary driving system in which overshoot is possible8. Synchronous command and asynchronous command

1. Block Diagram of Camera System

FIG. 1 is a block diagram illustrating an exemplary configuration of oneembodiment of a camera system according to the present technology.

A camera system 1 of FIG. 1 is a lens-interchangeable digital camera,and includes a detachable interchangeable lens 10 and a shootingapparatus 60 as a body.

The interchangeable lens 10 includes a mount part 21 detachably attachedto a mount part 71 of the shooting apparatus 60. The mount part 21 has aplurality of terminals (not illustrated) electrically connected to themount part 71 of the shooting apparatus 60.

Further, the interchangeable lens 10 includes a lens control unit 22, azoom lens 23, a blurring correction lens 24, a diaphragm 25, anobject-side focus lens 26, a device-side focus lens 27, an operationunit 28, a memory unit 29, a recording unit 30, a power source controlunit 31, and a temperature sensor 32.

The interchangeable lens 10 has two kinds of focus lenses including theobject-side focus lens 26 and the device-side focus lens 27 forautofocus control, where the object-side focus lens 26 is a focus lenscloser to an objective lens (not illustrated) out of the two kinds offocus lenses, and the device-side focus lens 27 is a focus lens closerto an imaging device 76 of the shooting apparatus 60. Additionally, eachof the object-side focus lens 26 and the device-side focus lens 27includes one or more optical elements.

The lens control unit 22 is configured of a computation processingapparatus such as central processing unit (CPU) or micro processing unit(MPU), a peripheral circuit, and the like, for example, and reads andexecutes predetermined control programs recorded in the recording unit30 thereby to control the entire interchangeable lens 10.

For example, the lens control unit 22 controls a position of the zoomlens 23 in response to an instruction from the shooting apparatus 60supplied via a predetermined communication terminal of the mount part 21or a user's operation received by the operation unit 28. Morespecifically, the lens control unit 22 acquires a current position ofthe zoom lens 23 from a zoom position detection unit 41, determines adriving direction and the driving amount for moving the zoom lens 23 toa predetermined position on the basis of the acquired result, andoutputs the determined driving direction and driving amount to a zoomdriving unit 42 together with a moving instruction. The zoom positiondetection unit 41 is configured of a magnetic sensor (MR sensor) or thelike, for example, detects a position of the zoom lens 23, and suppliesit to the lens control unit 22. The zoom driving unit 42 moves the zoomlens 23 in an optical axis direction to have the designated drivingdirection and driving amount in response to the moving instructionsupplied from the lens control unit 22.

Further, the lens control unit 22 controls the blurring correction lens24 to correct blurring. Specifically, the lens control unit 22determines a driving direction and the driving amount of the blurringcorrection lens 24 in a direction in which the blurring amount iscancelled on the basis of the blurring amount detected by a blurringdetection unit 43, and outputs the determined driving direction anddriving amount to a blurring driving unit 44 together with a movinginstruction. The blurring detection unit 43 is configured of a gyrosensor, a three-axis acceleration sensor, or the like. A gyro sensor isused to detect an offset (blurring) in a direction corresponding toPitch or Yaw as a correction direction of the blurring correction lens24, and a three-axis acceleration sensor is used to detect offsets(blurring) in the X-axis and Y-axis directions with the optical axisdirection as Z axis. The blurring detection unit 43 may include either agyro sensor or a three-axis acceleration sensor, or both of them. Theblurring driving unit 44 moves the blurring correction lens 24 to havethe designated driving direction and driving amount in response to themoving instruction supplied from the lens control 22.

The lens control unit 22 controls the aperture diameter of the diaphragm25 in response to an instruction and the like from the shootingapparatus 60 supplied via a predetermined communication terminal of themount part 21. Specifically, the lens control unit 22 acquires theaperture diameter of the diaphragm 25 detected by a diaphragm detectionunit 45, instructs a diaphragm driving unit 46 to set a F value(aperture value) designated by the shooting apparatus 60, and moves thediaphragm 25. The diaphragm driving unit 46 moves the diaphragm 25 tohave the aperture diameter designated by the lens control unit 22.

Further, the lens control unit 22 controls the two kinds of focus lensesincluding the object-side focus lens 26 and the device-side focus lens27. Specifically, the lens control unit 22 acquires a current positionof the object-side focus lens 26 from an object-side lens positiondetection unit 47, determines a driving direction and the driving amountfor moving the object-side focus lens 26 to a predetermined position onthe basis of the acquired result, and outputs the determined drivingdirection and driving amount to an object-side lens driving unit 48together with a moving instruction. The object-side lens driving unit 48moves the object-side focus lens 26 in the optical axis direction tohave the designated driving direction and driving amount. Similarly, thelens control unit 22 acquires a current position of the device-sidefocus lens 27 from a device-side lens position detection unit 49,determines a driving direction and the driving amount for moving thedevice-side focus lens 27 to a predetermined position on the basis ofthe acquired result, and outputs the determined driving direction anddriving amount to a device-side lens driving unit 50 together with amoving instruction. The device-side lens driving unit 50 moves thedevice-side focus lens 27 in the optical axis direction to have thedesignated driving direction and driving amount.

The object-side lens position detection unit 47 and the device-side lensposition detection unit 49 can be configured of a magnetic sensor, aphotodiode array, a potentiometer, a reflective encoder, or the like,for example.

The object-side lens driving unit 48 and the device-side lens drivingunit 50 may employ an ultrasonic motor, a DC motor, a linear actuator, astepping motor, a piezoelectric device, or the like, for example, but aDC motor or an ultrasonic motor is suitable when a heavy focus lens witha long lens diameter or a thick lens is driven. In a case where theinterchangeable lens 10 has two kinds of focus lenses including theobject-side focus lens 26 and the device-side focus lens 27, theobject-side focus lens 26 is generally heavier.

Additionally, the interchangeable lens 10 does not necessarily need tohave two kinds of focus lenses, and either the object-side focus lens 26or the device-side focus lens 27 may be omitted. In this case, the lensposition detection unit and the lens driving unit required forcontrolling the omitted focus lens are also omitted.

The operation unit 28 corresponds to a zoom ring configured to manuallyset a zoom magnification, a focus ring configured to manually set afocus lens, or the like, receives a user's manual operation, andsupplies an operation signal corresponding to the received operation tothe lens control unit 22.

The memory unit 29 is a volatile storage medium such as random accessmemory (RAM) and the like, and is used as a storage area for variousitems of data in use.

The recording unit 30 is a nonvolatile storage medium, and the recordingunit 30 stores therein various items of data such as predeterminedcontrol programs executed by the lens control unit 22, or adjustmentparameters.

The power source control unit 31 detects the amount of power suppliedfrom the shooting apparatus 60, optimally distributes the amount ofpower to the respective units (the lens control unit 22 or variousdriving units) in the interchangeable lens 10 on the basis of thedetected amount of power, and supplies them with power.

The temperature sensor 32 detects a temperature around or inside theinterchangeable lens 10, and supplies it to the lens control unit 22. Adetection result of the temperature sensor 32 is used to determine aparameter when considering a change in temperature.

On the other hand, the shooting apparatus 60 as a body includes themount part 71 to which the interchangeable lens 10 is detachablyattached. The mount part 71 has a plurality of terminals (notillustrated) electrically connected to the mount part 21 of theinterchangeable lens 10.

When the interchangeable lens 10 is mounted on the mount part 71 of theshooting apparatus 60, each terminal of the mount part 71 correspondingto each terminal of the mount part 21 of the interchangeable lens 10 areelectrically and physically connected. The connected terminals areaterminal for supplying power (power supply terminal), a terminal fortransmitting commands or data (communication terminal), a terminal fortransmitting synchronous signals (synchronous signal terminal), and thelike, for example.

The shooting apparatus 60 further includes a body control unit 72, amechanical shutter 73, a shutter detection unit 74, a shutter drivingunit 75, an imaging device 76, an image signal processing unit 77, arecording unit 78, a display unit 79, a power source control unit 80, apower source unit 81, and an operation unit 82.

The body control unit 72 is configured of a computation processingapparatus such as central processing unit (CPU) or micro processing unit(MPU), a nonvolatile memory, a peripheral circuit, and the like, forexample, and reads and executes predetermined control programs stored inan internal nonvolatile memory thereby to control the entire camerasystem 1.

For example, the body control unit 72 causes the imaging device 76 toshoot, transmits a predetermined command to the interchangeable lens 10via the mount part 71, and drives the focus lenses (the object-sidefocus lens 26 and the device-side focus lens 27), the zoom lens 23, andthe like in response to an operation signal indicating a user'spredetermined operation supplied from the operation unit 82.

Further, for example, the lens position information of the focus lenses,the zoom position information of the zoom lens 23, or the like issupplied from the interchangeable lens 10 to the body control unit 72via the mount part 71, and the body control unit 72 causes the imagingdevice 76 to shoot an image to be recorded in the recording unit 78 oran image to be transmitted to an external device at an optimum timingbased on the information. (The data of) the image acquired by theimaging device 76 is recorded (stored) in the recording unit 78 ordisplayed on the display unit 79 under control of the body control unit72.

The mechanical shutter 73 is arranged in front of the imaging device 76,and opens/closes under control of the shutter driving unit 75. When themechanical shutter 73 is closed, a light of an object passing throughthe optical system of the interchangeable lens 10 is shut. The shutterdetection unit 74 detects the opened/closed state of the mechanicalshutter 73, and supplies it to the body control unit 72. The shutterdriving unit 75 drives the mechanical shutter 73 to be opened or closedunder control of the body control unit 72.

The imaging device 76 is configure of a charge coupled device (CCD), acomplementary metal oxide semiconductor (CMOS) sensor, or the like, forexample, shoots an object, and generates and outputs image data thereof.

The imaging device 76 includes a pixel array part in which pixels(imaging pixels) configured to generate an image generation signal arearranged in a matrix shape. Further, some pixels in the pixel array partinclude phase difference pixels configure to generate a focus detectionsignal. In the phase difference pixels, part of a light receiving regionis shut by a light shielding film, and a focus offset can be detectedfrom pixel signals output from two phase difference pixels symmetricalwith respect to the optical axis in the light shielding region shut bythe light shielding film.

Additionally, in a case where the imaging device 76 is configured of aCCD sensor or a CMOS sensor, an electronic shutter can be used and themechanical shutter 73 can be omitted. In a case where the mechanicalshutter 73 is omitted, the shutter detection unit 74 and the shutterdriving unit 75 used for controlling the same are also omitted.

The image signal processing unit 77 performs a predetermined imagesignal processing on an image supplied from the imaging device 76. Forexample, the image signal processing unit 77 converts a RAW imagesupplied from the imaging device 76 into image data in a predeterminedfile format, and causes the recording unit 78 to record the image data.Further, the image signal processing unit 77 performs a demosaicprocessing on the RAW image, further performs lossless compression orlossy compression thereby to convert the RAW image into image data in apredetermined file format, and causes the recording unit 78 to recordthe image data. Further, for example, the image signal processing unit77 converts the image data supplied from the imaging device 76 into animage signal in a predetermined display format, supplies the imagesignal to the display unit 79, and causes the display unit 79 to displaythe shot image.

The recording unit 78 is configured of a nonvolatile memory, forexample, and records (stores) therein data of the images shot by theimaging device 76, and the like. A recording medium for the recordingunit 78 may be detachable.

The display unit 79 is configured of a panel-type display apparatus suchas liquid crystal panel or organic electro luminescence (EL) panel, anddisplays an image (moving picture or still image) supplied from theimage signal processing unit 77. The display unit 79 is mounted on theback opposed to the front on which the mount part 71 is arranged, andcan display a live view image, a preview image, or the like.

The power source control unit 80 supplies each unit in the shootingapparatus 60 with power supplied from the power source unit 81. Further,the power source control unit 80 calculates the amount of power capableof being supplied to the interchangeable lens 10 in consideration of anoperation state of the shooting apparatus 60, and supplies power to theinterchangeable lens 10 via the mount part 71. The power source unit 81is configured of a secondary battery such as NiCd battery, NiMH battery,or Li battery, an AC adapter, or the like, for example.

The operation unit 82 includes hardware keys such as release button,mode dial, and zoom button, and software keys on a touch panel laminatedon the display unit 79, receives a user's predetermined operation, andsupplies an operation signal thereof to the body control unit 72. Theuser operates the operation unit 82 thereby to set a shooting mode, toset a camera parameter, or the like, for example.

The interchangeable lens 10 and the shooting apparatus 60 configuringthe camera system 1 have the above configurations, respectively.Additionally, the shooting apparatus 60 as a camera main body will bedescribed below as a body 60.

2. Operations of Diaphragm

FIG. 2 is a diagram for explaining the operations of the diaphragm 25when the aperture diameter of the diaphragm 25 is changed.

The horizontal axis indicates time and the vertical axis indicates acontrol value of a motor (such as stepping motor) for changing theaperture diameter of the diaphragm 25, or the amount of light passingthrough the diaphragm 25 in the graph of FIG. 2.

For example, in a case where a predetermined F value is designated fromthe body control unit 72 to the lens control unit 22, the lens controlunit 22 instructs the diaphragm driving unit 46 to set the amount oflight corresponding to the designated F value (target light amountvalue), and the diaphragm driving unit 46 drives the diaphragm 25 at theamount of light designated by the lens control unit 22. Specifically,the diaphragm driving unit 46 drives the motor in order to change theaperture diameter of the diaphragm 25 from the start position P1 of thecurrent diaphragm 25 to the end position P2 of the diaphragm 25corresponding to the designated F value.

As illustrated in FIG. 2, the motor control value is changed at apredetermined speed gradient from the start position P1 toward the endposition P2, but the diaphragm 25 is configured of seven blades or thelike, for example, and is driven by the motor via the gear, the shaft,or the like so that the amount of light passing through the aperturediameter and the opening region of the diaphragm 25 changes withpredetermined delay (driving time lag) due to mechanical loose or thelike. Further, also after the motor control value reaches the endposition P2 and the motor finishes being driven, the aperture diameterof the diaphragm 25 changes due to elastic distortion or the like. Thus,overshoot or undershoot occurs as indicated in a broken line in FIG. 2,and the amount of light passing through the opening region of thediaphragm 25 converges on the target light amount value corresponding tothe end position P2 after a predetermined time elapses from the end ofmotor driving.

In a case where the aperture diameter of the diaphragm 25 is changed inthis way, it takes a predetermined time until the amount of lightpassing through the opening region of the diaphragm 25 converges withinan error range where it can be determined that the amount of lightreaches the target light amount value corresponding to the end positionP2 after the diaphragm driving operation of changing the motor controlvalue to a value corresponding to the end position P2. The operation inthe period until the amount of light converges on the target lightamount value after the diaphragm 25 finishes being driven is assumed asstabilization operation, and the state in the period is assumed asstabilized state. The stabilization operation is caused by a mechanicalstructure such as loose between gears or twist of the shaft, forexample. Additionally, the causes of overshoot or undershoot in variousmechanical structures of the diaphragm 25 will be described below withreference to FIG. 10 to FIG. 12.

A time required for the stabilization operation is different dependingon the kind or the like of the interchangeable lens 10, and has beenhandled by securing a constant margin on the body 60, for example.However, in a case where a time until the stabilized state is longerthan the time secured by the body 60, shooting is performed in a statewhere the amount of light of the diaphragm 25 is unstable (inaccurate).Alternatively, in a case where a time until the stabilized state isshorter than the time secured by the body 60, an unwanted time lag iscaused until the start of shooting.

Thus, the camera system 1 of FIG. 1 is configured such that whenreceiving a designated predetermined F value from the body control unit72, the lens control unit 22 returns the driving end time of thediaphragm 25 including the stabilization time indicating a time in thestabilized state.

3. Time chart of Shooting Processings

The processings until an image to be recorded starts being exposed afterthe release button full-press operation as an operation to start theshooting of the image to be recorded in the recording unit 78 will bedescribed with reference to the time chart in FIG. 3.

Additionally, the operations described in FIG. 3 are in the AF modesuitable when an object is moving, in which autofocusing works alsowhile the release button is being half-pressed, and are in thecontinuous AF mode for keeping focusing.

The horizontal axis direction of FIG. 3 indicates time, where one periodbetween broken lines corresponds to one cycle ( 1/60 sec, for example)defined by a synchronous signal or its multiplied or divided signal.

When the user performs the full-press operation while the release buttonis being half-pressed, the body control unit 72 of the body 60 keeps thefocus position (locks the focus) when the full-press operation isperformed in step S1. The diaphragm 25 is controlled at a lower valuethan the predetermined F value (such as “11”) in the state. The presentexample assumes that the F value is set at “8” in the focus lockedstate.

Then in step S2, the body control unit 72 transmits a command to changethe F value of the diaphragm 25 to a target F value determined by theuser setting or the like (denoted as target F value below), for example,to the lens control unit 22.

When receiving the target F value command transmitted from the bodycontrol unit 72, the lens control unit 22 of the interchangeable lens 10calculates a driving end time of the diaphragm 25 including thestabilization time (denoted as diaphragm driving end time below) forchanging the F value from a current F value (denoted as current F valuebelow) to the target F value, and transmits it to the body control unit72 in step S3. It is assumed herein that the lens control unit 22calculates a time until time T1 of FIG. 3 as the diaphragm driving endtime and transmits it to the body control unit 72.

Additionally, the diaphragm driving end time transmitted from the lenscontrol unit 22 to the body control unit 72 may be a time until thediaphragm 25 finishes being driven (required time), or a time when thediaphragm 25 finishes being driven, or information indicating thedriving end timing of the diaphragm 25. Further, the informationindicating the driving end timing of the diaphragm 25 may be informationcorresponding to a time when the diaphragm 25 finishes being driven, orinformation with a predetermined width (time) including at least thetime when the diaphragm 25 finishes being driven.

Subsequently in step S4, the lens control unit 22 supplies a drivinginstruction to the diaphragm driving unit 46, and causes it to startdriving the diaphragm 25 for the target F value.

Additionally, any of the processings in steps S3 and S4 may be startedearlier, or may be performed at the same time. That is, the order of thetiming when the diaphragm 25 starts being driven and the timing when thelens control unit 22 transmits the diaphragm driving end time to thebody control unit 72 is not considered.

When receiving the diaphragm driving end time transmitted from the lenscontrol unit 22, the body control unit 72 calculates an exposure starttiming as a timing to cause the imaging device 76 to start exposing animage to be recorded in step S5.

The exposure start timing in step S5 is calculated as follows, forexample. At first, the body control unit 72 predicts (calculates) afocus position when the diaphragm driving end time elapses on the basisof a motion of an object detected when the object is focused in therelease button half-pressed state. The body control unit 72 thenpredicts (calculates) a focus driving time when a current focus positionis moved to the predicted focus position on the basis of a differencebetween the predicted focus position and the current focus position. Thebody control unit 72 then calculates the exposure start timing when animage to be recorded can start being exposed on the basis of thecalculated focus driving time and the diaphragm driving end timetransmitted from the lens control unit 22. The exposure start timingcorresponds to the longer time out of the focus driving time and thediaphragm driving end time.

In step S6, the body control unit 72 transmits a moving command to movethe focus lens (at least one of the object-side focus lens 26 or thedevice-side focus lens 27) to the focus target position as a focusposition when the diaphragm driving end time elapses, which iscalculated in the processing in step S5.

Therefore, when receiving the diaphragm driving end time transmittedfrom the lens control unit 22, the body control unit 72 controls thefocus lens (focus control) and determines the exposure start timing.

In step S7, the lens control unit 22 performs a focus driving processingof driving the focus lens to the focus target position in response tothe focus lens moving command transmitted from the body control unit 72.

Then, when the focus lens completely moves to the focus target position,in step S8, the lens control unit 22 transmits the end of focus lensdriving to the body control unit 72.

The body control unit 72 receives the end of focus lens driving, andthen causes the imaging device 76 to start exposing (capturing) forshooting an image to be recorded in step S9 at time T1 when thediaphragm driving end time elapses.

Time T1 is when the diaphragm 25 finishes being driven including thestabilization time, and thus shooting can be started in consideration ofmechanical fluctuations after the diaphragm is driven. In other words,an image to be recorded can start being shot at a timing not influencedby overshoot or undershoot of the diaphragm 25.

4. How to Calculate Diaphragm Driving End Time

How to calculate the diaphragm driving end time performed by the lenscontrol unit 22 will be described below with reference to FIG. 4.

At first, a driving plan of the diaphragm 25 is calculated on the basisof the current F value, the target F value, the diaphragm driving mode,individual adjustment data, and the like.

Here, the driving plan of the diaphragm 25 is information indicating achange (gradient) of the motor control value over time indicated in asolid line in the diaphragm driving operation in the graph of FIG. 2,and indicates how the motor control value is changed from the current Fvalue to the target F value. A time required for the subsequentstabilization operation changes depending on a gradient of the motorcontrol value.

For example, as indicated in the solid line of the diaphragm drivingoperation in the graph of FIG. 2, the lens control unit 22 calculatesthe driving plan to drive the first ¾ of the moving distance from thestart position P1 to the end position P2 at a first driving speed and todrive the last ¼ to the end position P2 at a second driving speed lowerthan the first driving speed. Additionally, the driving plan does notneed to be linearly controlled.

The diaphragm driving mode is a high-speed driving mode, a low-speeddriving mode, and the like, for example, and is a driving speed modecapable of being changed by user setting. The individual adjustment datais parameters for adjusting an individual difference of theinterchangeable lens 10.

The lens control unit 22 calculates the motor driving time according tothe driving plan of the diaphragm 25 calculated on the basis of thecurrent F value, the target F value designated by the body control unit72, the current diaphragm driving mode setting, the individualadjustment data, and the like.

The lens control unit 22 then calculates the stabilization time of thediaphragm 25 as a time until the amount of light converges on the targetlight amount value after the end of motor driving on the basis of aconvergence waveform in which the amount of light passing through thediaphragm 25 converges on the target light amount value over time.

For example, a function indicating the convergence characteristics isstored as a convergence waveform in the recording unit 30, and the lenscontrol unit 22 calculates the stabilization time of the diaphragm 25 onthe basis of the function indicating the convergence characteristicsstored in the recording unit 30. The function indicating the convergencecharacteristics may be assumed as a function having the parameters suchas an environment temperature detected by the temperature sensor 32, aposture (tilted state) of the interchangeable lens 10 detected by a gyrosensor or the like, a value indicating an aged state of theinterchangeable lens 10, and the like.

Further, the lens control unit 22 may store table data aspreviously-measured convergence time (stabilization time) until theamount of light passing through the diaphragm 25 converges on the targetlight amount value over time after the motor stops being driven in therecording unit 30, and may calculate the stabilization time of thediaphragm 25 by use of the table data.

More specifically, as illustrated in FIG. 5, for example, the table datain which the convergence time (stabilization time) until the amount oflight converges on the target light amount value is associated with acombination of the current F value and the target F value to be storedis stored in the recording unit 30, and the lens control unit 22calculates the stabilization time of the diaphragm 25 by use of thetable data.

Such table data can be created by use of the convergence time actuallymeasured in the interchangeable lens 10, for example. Further, the tabledata can be created per external environment condition or use condition.For example, a plurality of items of table data are distributed perenvironment temperature as an external environment condition, and thelens control unit 22 switches the table data to be used and calculatesthe stabilization time depending on a current temperature detected bythe temperature sensor 32. Further, for example, table data is providedper posture (tilted state) of the interchangeable lens 10 as a usecondition, and the lens control unit 22 switches the table datadepending on a posture detected by a gyro sensor or the like to be used,and calculates the stabilization time. Further, for example, as a usecondition, table data may be switched for calculation depending on anaged state of the interchangeable lens 10. For example, the integratedvalue of the driving amount when the diaphragm 25 is driven is stored asan aged state of the interchangeable lens 10, and the lens control unit22 switches and uses table data prepared per predetermined range of theintegrated value, and calculates the stabilization time.

FIG. 6 illustrates still other exemplary table data.

In the table data of FIG. 6, not taking the current F value intoconsideration, the convergence time until the amount of light convergeson the target light amount value is stored depending on the combinationsof two cases where the target F value is less than F8 and is F8 or moreand two cases where the current temperature detected by the temperaturesensor 32 is less than 40° C. and is 40° C. or more.

The lens control unit 22 adds the motor driving time as calculatedabove, and the stabilization time of the diaphragm 25 thereby tocalculate the diaphragm driving end time including the stabilizationtime.

Further, in a case where the lens control unit 22 does not start drivingthe diaphragm 25 for the target F value when transmitting the diaphragmdriving end time to the body control unit 72, the waiting time until thediaphragm 25 starts being driven (diaphragm start waiting time) is alsoincluded in calculation of the diaphragm driving end time. In a casewhere the processings in steps S3 and S4 of FIG. 3 are performed at thesame time or the processing in step S4 is started earlier than theprocessing in step S3, the diaphragm start waiting time is not includedin the diaphragm driving end time. To the contrary, in a case where theprocessing (of starting driving the diaphragm) in step S4 is performedearlier than the processing (of transmitting the diaphragm driving endtime) in step S3, the diaphragm driving end time is calculated except atime after the diaphragm driving unit 46 starts driving the diaphragm 25and until the diaphragm driving end time is transmitted to the bodycontrol unit 72.

5. Flowchart

The processings until an image to be recorded starts being exposed afterthe release button full-press operation will be described below withreference to the flowchart of FIG. 7.

When the user performs the release button full-press operation, in stepS21, the body control unit 72 keeps the focus position (locks the focus)when the full-press operation is performed.

In step S22, the body control unit 72 transmits a command to change theF value (aperture value) of the diaphragm 25 to the target F value.

In step S41, the lens control unit 22 of the interchangeable lens 10receives the command to change the F value to the target F valuetransmitted from the body control unit 72.

Then in step S42, the lens control unit 22 calculates the diaphragmdriving end time including the stabilization time when changing the Fvalue from the current F value to the target F value.

In step S43, the lens control unit 22 supplies a driving instruction tothe diaphragm driving unit 46, and causes it to start driving thediaphragm 25 for the target F value.

In step S44, the lens control unit 22 transmits the diaphragm drivingend time including the stabilization time calculated in the processingin step S42 to the body control unit 72.

Additionally, the processing in step S44 may be performed earlier thanthe processing in step S43, or steps S43 and S44 may be performed at thesame time.

In a case where the driving for the target F value is earlier started,the diaphragm driving end time does not include the waiting time untilthe diaphragm 25 starts being driven (diaphragm start waiting time). Onthe other hand, in a case where the diaphragm driving end time isearlier transmitted and a predetermined waiting time is caused untildriving is started, the diaphragm start waiting time is also included inthe diaphragm driving end time.

The body control unit 72 receives the diaphragm driving end timetransmitted from the body control unit 72 in step S23, and calculatesthe exposure start timing to cause the imaging device 76 to startexposing an image to be recorded in step S24. The exposure start timingis determined on the basis of the focus driving time until the focuslens moves to the focus target position, and the diaphragm driving endtime as described above.

Then in step S25, the body control unit 72 transmits, to the lenscontrol unit 22, a moving command to move the focus lens to the focustarget position with the focus predicted position when the diaphragmdriving end time elapses as the focus target position.

In step S45, the lens control unit 22 of the interchangeable lens 10receives the focus lens moving command transmitted from the body controlunit 72, and starts driving the focus lens.

Then in step S46, the lens control unit 22 determines whether or not thefocus lens finishes being driven to the designated focus targetposition, and waits until it is determined that the focus lens finishesbeing driven.

Then in step S46, in a case where it is determined that the focus lensfinishes being driven, the processing proceeds to step S47, where thelens control unit 22 transmits the end of focus lens driving to the bodycontrol unit 72.

After the body 60 transmits a moving command to move the focus lens tothe focus target position in step S25, the processing proceeds to stepS26, where the body control unit 72 determines whether or not the focuslens finishes being driven or whether or not the end of focus lensdriving is transmitted from the lens control unit 22.

In step S26, the processing waits until it is determined that the focuslens finishes being driven.

Then in step S26, in a case where it is determined that the focus lensfinishes being driven, the processing proceeds to step S27, where thebody control unit 72 determines whether or not the diaphragm 25 finishesbeing driven or whether or not the time when the diaphragm 25 finishesbeing driven corresponding to the diaphragm driving end time received instep S23 is reached.

In step S27, the processing waits until it is determined that thediaphragm 25 finishes being driven.

Then in step S27, in a case where it is determined that the diaphragm 25finishes being driven, the processing proceeds to step S28, where thebody control unit 72 causes the imaging device 76 to start exposing(capturing) for shooting an image to be recorded.

After the end of exposure, an image signal of the image to be recordedoutput from the imaging device 76 is recoded in the recording unit 30.

As described above, in the camera system 1 according to the technologyof the present disclosure, the lens control unit 22 of theinterchangeable lens 10 calculates the diaphragm driving end timingincluding the stabilization time when the diaphragm driving unit 46drives the diaphragm 25 in response to a command to drive the diaphragm25 from the body control unit 72, and transmits it as diaphragm drivinginformation to the body control unit 72.

The body control unit 72 can accurately grasp the diaphragm driving endtiming including the stabilization time, and can further shorten thetime until the start of shooting (can further speed up shooting) than ina case where a certain margin is secured for an unknown stabilizationtime in the body 60, for example, thereby contributing to an improvementin focusing accuracy.

Further, exposure for shooting an image to be recorded can be started ata timing not influenced by overshoot or the like of the diaphragm 25,thereby improving the shot image exposure accuracy.

Further, in a case where a phase difference is detected, the unstablediaphragm influences the phase difference detection accuracy. The phasedifference is detected at the diaphragm driving end timing including thestabilization time, thereby improving the phase difference detectionaccuracy.

Further, the driving end timing of the diaphragm 25 when overshoot bydriving the diaphragm 25 ends and is stabilized is provided innotification to the body 60 before the end of driving, and is used tocalculate the next shooting start timing, thereby shortening theshooting interval when continuously shooting as in the continuousshooting, and further improving the focusing accuracy.

6. Exemplary Processings when Calculating Diaphragm Driving End Time inBody

The above example describes that the lens control unit 22 of theinterchangeable lens 10 calculates the diaphragm driving end time andtransmits it as diaphragm driving information to the body control unit72, and how to calculate the diaphragm driving end time in the body 60will be described below. In this case, the body control unit 72 acquiresthe parameters required for calculating the diaphragm driving end time(denoted as diaphragm driving parameters below) as diaphragm drivinginformation from the lens control unit 22, and calculates the diaphragmdriving end time.

A processing of acquiring the diaphragm driving parameters from the lenscontrol unit 22 by the body control unit 72 will be described withreference to the flowchart of FIG. 8. The processing is performed aspart of initialization processings when the interchangeable lens 10 ismounted on the body 60, for example.

When the user mounts the interchangeable lens 10 on the body 60, in stepS141, the body control unit 72 transmits a diaphragm driving parameterrequest to ask the interchangeable lens 10 for the diaphragm drivingparameters to the interchangeable lens 10.

In step S161, the lens control unit 22 of the interchangeable lens 10receives the diaphragm driving parameter request transmitted from thebody control unit 72.

Then in step S162, the lens control unit 22 transmits the diaphragmdriving parameters to the body control unit 72. The diaphragm drivingparameters include parameters for computing a driving time of thediaphragm 25 including the information indicating the stabilization time(stabilization time information). Examples of the parameters areinformation for calculating a diaphragm driving trajectory such as motoracceleration/deceleration rate and maximum speed limit value,information for calculating the stabilization time such as relationshipbetween position and F value of the diaphragm 25 and table data storingconvergence waveform and convergence time, and the like, for example.

In step S142, the body control unit 72 receives the diaphragm drivingparameters transmitted from the lens control unit 22 and stores them inthe internal memory or the like.

This is the end of the processing of acquiring the diaphragm drivingparameters. Additionally, the processing of acquiring the diaphragmdriving parameters may be performed as part of a series ofinitialization processings when the interchangeable lens 10 is mountedon the body 60, or may be performed at other timing such as immediatelybefore the diaphragm 25 is first moved, for example. In other words, thebody control unit 72 can perform the processing at any timing before thediaphragm 25 is first moved.

The processings after the release button is fully pressed and until animage to be recorded starts being exposed in a case where the body 60calculates the diaphragm driving end time will be described below withreference to the flowchart of FIG. 9.

When the user performs the release button full-press operation, in stepS201, the body control unit 72 keeps the focus position (locks thefocus) when the full-press operation is performed. In this state, thediaphragm 25 is controlled at a lower value than the predetermined Fvalue (such as “11”). The present example assumes that the F value isset at “8” in the focus locked state.

In step 5202, the body control unit 72 calculates the diaphragm drivingend time for changing the F value of the diaphragm 25 from the current Fvalue to the target F value by use of the diaphragm driving parameterspreviously acquired from the lens control unit 22 of the interchangeablelens 10.

In step S203, the body control unit 72 calculates the focus drivingtime. Specifically, the body control unit 72 predicts a focus positionwhen the diaphragm driving end time elapses on the basis of a motion ofan object detected when the object is focused in the release buttonhalf-pressed state. The body control unit 72 then predicts a focusdriving time when the focus lens is moved to the predicted focusposition on the basis of a difference between the predicted focusposition and the current focus position.

In step S204, the body control unit 72 determines the exposure starttiming. The exposure start timing corresponds to the longer time out ofthe focus driving time and the diaphragm driving end time.

In step S205, the body control unit 72 transmits, to the lens controlunit 22, a moving command to move the focus lens to the focus targetposition with the focus predicted position when the diaphragm drivingend time elapses as the focus target position.

In step S221, the lens control unit 22 of the interchangeable lens 10receives the focus lens moving command transmitted from the body controlunit 72 and starts driving the focus lens.

After the body 60 transmits the moving command to move the focus lens tothe focus target position in step S205, the processing proceeds to stepS206, where the body control unit 72 transmits a command to change the Fvalue of the diaphragm 25 to the target F value to the lens control unit22.

In step S222, the lens control unit 22 of the interchangeable lens 10receives the command to change the F value to the target F valuetransmitted from the body control unit 72, supplies a drivinginstruction to the diaphragm driving unit 46, and starts driving thediaphragm 25 for the target F value.

In the interchangeable lens 10, the processing ends when the movement ofthe focus lens to the focus target position and the movement of thediaphragm 25 to the target F value end.

After the body 60 transmits a command to change the F value of thediaphragm 25 to the target F value in step S206, the processing proceedsto step S207, where the body control unit 72 determines whether or notthe exposure start timing is reached.

In step S207, the processing waits until it is determined that theexposure start timing is reached.

Then in step S207, in a case where it is determined that the exposurestart timing is reached, the processing proceeds to step S208, where thebody control unit 72 causes the imaging device 76 to start exposing(capturing) for shooting an image to be recorded.

After the end of exposure, an image signal of the image to be recordedoutput from the imaging device 76 is recorded in the recording unit 30.

As described above, the body control unit 72 of the body 60 maycalculate the diaphragm driving end time on the basis of the diaphragmdriving parameters previously acquired as diaphragm driving informationfrom the interchangeable lens 10. The body control unit 72 can acquireeach parameter for calculating the diaphragm driving end timingincluding the stabilization time of the diaphragm 25 described withreference to FIG. 4 as a diaphragm driving parameter from theinterchangeable lens 10. Also in this case, the body control unit 72 canaccurately grasp the diaphragm driving end timing including thestabilization time, and thus can further shorten a time until the startof shooting (can further speed up shooting) than in a case where acertain margin is secured for an unknown stabilization time in the body60, for example, thereby contributing to an improvement in focusingaccuracy.

Further, exposure for shooting an image to be recorded can be started ata timing not influenced by overshoot or the like of the diaphragm 25,thereby improving the shot image exposure accuracy.

Further, in a case where a phase difference is detected, the unstablediaphragm influences the phase difference detection accuracy. The phasedifference is detected at the diaphragm driving end timing including thestabilization time, thereby improving the phase difference detectionaccuracy.

7. Exemplary Driving System Where Overshoot is Possible

Points which can be causes of overshoot or undershoot in various lightamount adjustment mechanisms capable of being employed as the diaphragm25 will be described below.

First Light Amount Adjustment Apparatus

FIG. 10 illustrates an exploded view of a first light amount adjustmentapparatus capable of being employed as the diaphragm 25.

The first light amount adjustment apparatus illustrated in FIG. 10 is alight amount adjustment apparatus 100 described in Japanese PatentApplication Laid-Open No. 2014-164106.

The light amount adjustment apparatus 100 has a main motor 101 as afirst motor, an auxiliary motor 102 as a second motor, a main rotationmember 103 as a first rotation member, an auxiliary rotation member 104as a second rotation member, an upper cover 105 as a first cover, alower cover 106 as a second cover, and a diaphragm blade 107 as a lightamount adjustment member.

The main motor 101 employs a stepping motor in order to performpositioning control on the main rotation member 103. The main motor 101is fixed on the upper cover 105, and is driven and controlled by thecontrol unit provided in the camera main body (not illustrated). Anoutput gear 101 a attached to the main motor 101 meshes with a gear part103 a provided on the main rotation member 103, and transmits the outputof the main motor 101 to the main rotation member 103. Thereby, the mainrotation member 103 is guided to a fitting part of the upper cover 105to be rotated and driven around the optical axis.

The main rotation member 103 has hole parts 103 b, and the lower cover106 has cam grooves 106 a. The diaphragm blade 107 is provided withdowels 107 a and 107 b, the dowels 107 a fit with the hole parts 103 bprovided on the main rotation member 103, and the dowels 107 b fit withthe cam grooves 106 a provided on the lower cover 106. FIG. 10illustrates that the diaphragm blade 107 is configured of six blades,and thus illustrates a configuration in which six hole parts 103 b, sixcam grooves 106 a, six dowels 107 a, and six dowels 107 b are provided.

The main rotation member 103, the upper cover 105, and the lower cover106 have a ring shape, respectively, and a through-hole including theoptical axis is assumed as an optical path. When the main rotationmember 103 is rotated and driven by the main motor 101, the dowels 107 aof the diaphragm blade 107 fit into the hole parts 103 b rotate togetherwith the main rotation member 103 around the optical axis so that thedowels 107 b are guided along the cam grooves 106 a. When the main motor101 is driven and controlled to rotate the main rotation member 103 inthe diaphragm direction, the diaphragm blade 107 approaches the opticalaxis so that the amount of light passing through the optical path isadjusted. On the other hand, the main motor 101 is driven and controlledto rotate the main rotation member 103 in the open direction, therebyreturning the diaphragm blade 107 to the open diameter.

In the light amount adjustment apparatus 100, fluctuations due to atension between the stop holding force of the main motor 101 and theinertia force of all the driving members from the output gear 101 aattached to the main motor 101 to the gear part 103 a, the hole parts103 b, the dowels 107 a, the dowels 107 b, and the cam grooves 106 a,fluctuations due to play between driving members or due to distortion ordeflection between driving members, fluctuations due to deflection ofthe diaphragm blade 107, and the like can be a cause of overshoot orundershoot.

Second Light Amount Adjustment Apparatus

FIG. 11 illustrates an exploded view of a second light amount adjustmentapparatus capable of being employed as the diaphragm 25.

The second light amount adjustment apparatus illustrated in FIG. 11 isan exposure control mechanism 120 described in Japanese PatentApplication Laid-Open No. 2001-272709.

The exposure control mechanism 120 is configured of first and seconddiaphragm blades 122 and 123, an ND filter 124 attached to the firstdiaphragm blade 122, a driving means 125 configured to drive the firstand second diaphragm blades 122 and 123, a casing 126 fixed with thedriving means 125, and the like as illustrated in FIG. 11.

The first and second diaphragm blades 122 and 123 include a relativelyflexible resin film, for example, and the first diaphragm blade 122 isarranged closer to an object and the second diaphragm blade 123 isarranged closer to an image in an imaging lens system (not illustrated)of the shooting apparatus.

The first diaphragm blade 122 is formed at its upper edge with a cutout127 for forming a diaphragm opening, and is formed with guided slits 128and 128 and a guided slit 129, which vertically extend, closer to theright edge and closer to the left edge, respectively. Further, it isformed with a horizontally-extending coupling long hole 130 closer tothe lower edge.

The cutout 127 for forming a diaphragm opening of the first diaphragmblade 122 is opened at the upper edge, and its shape is such that theupper half 127 a relative to almost the center in the vertical directionhas the same right and left widths, the lower half 127 b is narrowerdownward, and the lower edge (denoted as “triangle part” below) 127 c isformed in a flat triangle.

The ND filter 124 is formed such that an upper part 124 a and a lowerpart 124 b are different in density to have different transmissivity,respectively, where the upper part 124 a has a transmissivity of about33% and the lower part 124 b has a transmissivity of about 10%. Then,the ND filter 124 is attached such that the upper part 124 a covers theupper half 127 a of the cutout 127 for forming a diaphragm opening ofthe first diaphragm blade 122 and the lower part 124 b covers the lowerhalf 127 b of the cutout 127 for forming a diaphragm opening of thefirst diaphragm blade 122.

The second diaphragm blade 123 has a shape in which a lower part almostin the left half is cut out or a shape in which the lower edge of theright half extends lower than the left half, and is formed at its upperposition with an opening 131 for forming a diaphragm opening, and guidedslits 132 and 132 and a guided slit 133, which vertically extend, closerto the right edge and closer to the left edge, respectively. Further, ahorizontally-extending coupling long hole 134 is formed closer to thelower edge in the downward-extending right half or immediately below thelower right guided slit 132.

The opening 131 for forming a diaphragm opening is such that itsentirety 131 a (denoted as “circular part” below) is almost circular andits upper edge (denoted as “triangular part” below) 11 b is a flattriangle.

The casing 126 is formed with a light passing hole 135 closer to thetop, a vertically-long arc-like long hole 136 at a lower left position,and a vertically-long arc-like long hole 137 at a lower right position.Further, one guide pin 138 and two guide pins 138 and 138, which engagewith the guided slits 128, 128, 129, 132, 132, and 133 of the first andsecond diaphragm blades 122 and 123 as described below, are formed toprotrude forward (toward an object) on the left side and on the rightside, respectively, substantially at the center of the casing 136.

The driving means 125 is configured of a driving motor 139 fixed on thecasing 126 from behind in an appropriate manner, and an operation arm140 fixed on a rotation shaft 139 a of the driving motor 139.

The operation arm 140 is fixed at its center on the rotation shaft 139 aof the driving motor 139. Then, the operation arm 140 has arm parts 141a and 141 b extending in opposite directions, a coupling pin 142 a isprotruded at the tip of the left arm part 141 a, a coupling pin 142 b isprotruded at the tip of the right arm part 141 b, and the left arm part141 a is formed to be longer than the right arm part 141 b.

Then, the coupling pin 142 a at the left end and the coupling pin 142 bat the right end are slidably engaged with the coupling long hole 130 ofthe first diaphragm blade 122 and the coupling long hole 134 of thesecond diaphragm blade 123, respectively.

Therefore, when the operation arm 140 rotates, the coupling pins 142 aand 142 b thereof vertically move in opposite directions, and thus thefirst diaphragm blade 122 and the second diaphragm blade 123 verticallymove in opposite directions. Further, the distance of the coupling pin142 a from the rotation shaft 139 a is longer than that of the couplingpin 142 b, and thus the first diaphragm blade 122 is faster moved thanthe second diaphragm blade 123.

Then, the first diaphragm blade 122 and the second diaphragm blade 123vertically move in opposite directions, and thus the size of an openingwhere the cutout 127 for forming a diaphragm opening and the opening 131for forming a diaphragm opening overlap or a diaphragm opening changes.

In the exposure control mechanism 120, fluctuations due to a tensionbetween the stop holding force of the driving motor 139 and the inertiaforce of all the driving members from the coupling pins 142 a and 142 bof the operation arm 140 fixed on the rotation shaft 139 a of thedriving motor 139 to the coupling long hole 130 of the first diaphragmblade 122 and the coupling long hole 134 of the second diaphragm blade123 slidably engaged with the coupling pins 142 a and 142 b,respectively, fluctuations due to play between driving members or due todistortion or deflection between driving members, and the like can be acause of overshoot or undershoot.

Third Light Amount Adjustment Apparatus

FIG. 12 is a cross-section view illustrating a configuration of a thirdlight amount adjustment apparatus capable of being employed as thediaphragm 25.

The third light amount adjustment apparatus illustrated in FIG. 12 is alinearly-driven light amount control apparatus 160 of electromagneticlevitation type described in Japanese Patent Application Laid-Open No.2-226130.

In FIG. 12, a cover 171 of the light amount control apparatus 160 has anopening 171 a, and is mounted on its inner periphery with a pair oflight amount control member magnets 172 a and 172 b across the opening171 a, a driving coil 173 configured to control moving a light amountcontrol member 176, a speed detection coil 174, and a back yoke 175.

On the other hand, a base board 182 as a base has an opening 182 a, andis mounted on its inner periphery with a pair of light amount controlmember support magnets 181 a and 181 b across the opening 182 a, adriving coil 178 configured to control moving a light amount controlmember 177, a speed detection coil 179, and a back yoke 180.

Then, the light amount control members 176 and 177 are arranged betweenthe cover 171 and the base board 182, have the openings 176 a and 177 a,respectively, and are magnetized to repel each other, and the lightamount control member support magnets 172 a and 172 b and 181 a and 181b are magnetized to repel each other.

In the above configuration, the light amount control members 176 and 177are floating due to repulsion between the magnetic force of the lightamount control member support magnets 172 a and 172 b and 181 a and 181b and the magnetic force of the light amount control members 176 and177, and are not in contact.

Thus, when a current flows in the driving coils 173 and 178, a drivingforce is generated due to the magnetic force of the light amount controlmembers 176 and 177 so that the light amount control members 176 and 177slide in opposite directions.

In the light amount control apparatus 160, fluctuations due to a tensionbetween the stop holding force of the driving coils 173 and 178 and theinertia force of the light amount control members 176 and 177, and thelike can be a cause of overshoot or undershoot.

8. Synchronous Command and Asynchronous Command

In the camera system 1 of FIG. 1, one or more commands transmitted atthe same timing are packetized into one packet to be transmitted inpacket communication. One packet is configured of a header, a command,and a footer, where the header is added ahead of the command and thefooter is added behind the command. The footer includes a checksum forconfirming the presence of a communication error of the command on thereception side.

Commands exchanged between the lens control unit 22 and the body controlunit 72 include two kinds of commands such as synchronous command formaking communication in synchronization with a synchronous signal andasynchronous command for making communication at any timing irrespectiveof a timing of a synchronous signal. Here, the synchronous signals usedfor the synchronous command include asynchronous signal itselftransmitted via a synchronous signal terminal and a divided ormultiplied signal of the synchronous signal. That is, the lens controlunit 22 makes communication with the body control unit 72 in thesynchronous command on the basis of a synchronous signal or a divided ormultiplied signal of the synchronous signal. In a case wherecommunication based on a divided or multiplied signal of the synchronoussignal is made, the lens control unit 22 performs a processing ofgenerating a signal obtained by dividing or multiplying the synchronoussignal transmitted via the synchronous signal terminal.

Asynchronous command is communicated in synchronization with asynchronous signal, and thus a timing to transmit a second synchronouscommand after transmitting a first synchronous command is to be a timingof a synchronous signal subsequent to the synchronous signaltransmitting the first synchronous command.

The synchronous command is used as a command to notify the body controlunit 72 of a lens state of the interchangeable lens 10 from the lenscontrol unit 22, for example. Specifically, the synchronous command isused when the lens control unit 22 transmits the position information ofthe zoom lens 23, the diaphragm 25, the object-side focus lens 26, andthe device-side focus lens 27. Further, the synchronous command is usedalso in a case where the body control unit 72 instructs the lens controlunit 22 on a predetermined operation.

To the contrary, the asynchronous command is used to rapidly notify thebody control unit 72 of the occurrence of a communication error in acase where the communication error of the command occurs in theinterchangeable lens 10, for example. That is, when detecting thepresence of a communication error of the command transmitted from thebody control unit 72 by determining the checksum, and detecting acommunication error, the lens control unit 22 transmits the occurrenceof the communication error in an asynchronous command to the bodycontrol unit 72. Thereby, the body control unit 72 which receives theasynchronous command indicating the occurrence of the commination errorcan rapidly perform a recovery processing of recovering thecommunication error.

Further, the synchronous command is used for a command to change the Fvalue to the target F value, a command to transmit the diaphragm drivingend time, and a moving command (including data) to move the focus lens,which are transmitted between the lens control unit 22 and the bodycontrol unit 72 in the above shooting processing.

Additionally, in a case where the control unit on the reception side(the lens control unit 22 or the body control unit 72) normally receivesa command via the communication terminal, it may return a responseindicating the reception of the command or may not return a responsedepending on the kind of the received command.

A command transmission control processing, which is a control processingof transmitting a command from the lens control unit 22 to the bodycontrol unit 72, will be described with reference to the flowchart ofFIG. 13. The command transmission control processing of FIG. 13 isrepeatedly performed at a cycle of multiplied synchronous signal or ashorter cycle than the multiplied cycle, for example.

At first, in step 5101, the lens control unit 22 determines whether ornot a synchronous command transmission timing is reached.

In a case where it is determined in step S101 that a synchronous commandtransmission timing is reached, in step S102, the lens control unit 22determines whether or nota synchronous command to be transmitted to thebody control unit 72 is present.

In a case where the lens control unit 22 generates a synchronous commandto be transmitted to the body control unit 72 along with the control ofthe interchangeable lens 10 such as focus lens position information orthe like, the lens control unit 22 stores it in a queue buffer forsynchronous commands inside the lens control unit 22. In step S102, thelens control unit 22 determines whether or not a synchronous command tobe transmitted to the body control unit 72 is present in the queuebuffer for synchronous commands.

In a case where it is determined in step S102 that asynchronous commandto be transmitted to the body control unit 72 is present, the processingproceeds to step S103, where the lens control unit 22 determines whetheror not an asynchronous command to be transmitted to the body controlunit 72 is present.

In a case where the lens control unit 22 generates an asynchronouscommand to be transmitted to the body control unit 72 along with thecontrol of the interchangeable lens 10 such as focus lens driving amountinformation or the like, the lens control unit 22 stores it in a queuebuffer for asynchronous commands inside the lens control unit 22. Instep S103, the lens control unit 22 determines whether or not anasynchronous command to be transmitted to the body control unit 72 ispresent in the queue buffer for asynchronous commands.

In a case where it is determined in step S103 that an asynchronouscommand is present, the processing proceeds to step S104, where the lenscontrol unit 22 transmits the synchronous command and the asynchronouscommand present in the queue buffers in the same packet to the bodycontrol unit 72, and terminates the processing.

FIG. 14 is a time chart illustrating exemplary packet communication madein step S104.

In FIG. 14, the cycle of a synchronous signal is 1/60 sec and theminimum transmission interval of a synchronous command is 1/60 sec.

In a case where an a synchronous command is present at a synchronouscommand transmission timing, a synchronous command and an a synchronouscommand are multiplexed and transmitted in one packet as illustrated inFIG. 14. The state in which asynchronous command and an asynchronouscommand are in contact in FIG. 14 indicates that the synchronous commandand the asynchronous command are transmitted in one packet.

On the other hand, in a case where it is determined in step S103 that anasynchronous command is not present, the processing proceeds to stepS105, where the lens control unit 22 transmits only the synchronouscommand in a packet to the body control unit 72, and terminates theprocessing.

FIG. 15 is a time chart illustrating exemplary packet communication madein step S105.

In a case where an asynchronous command is not present at a synchronouscommand transmission timing, only the synchronous command is transmittedin one packet as illustrated in FIG. 15.

On the other hand, in a case where it is determined in step S101 that asynchronous command transmission timing is not reached or in a casewhere it is determined in step S102 that a synchronous command to betransmitted to the body control unit 72 is not present, the processingproceeds to step S106, where the lens control unit 22 determines whetheror not an asynchronous command to be transmitted to the body controlunit 72 is present in the queue buffer for asynchronous commands.

In a case where it is determined in step S106 that an asynchronouscommand is present, the processing proceeds to step S107, where the lenscontrol unit 22 transmits only the asynchronous command in a packet tothe body control unit 72, and terminates the processing.

FIG. 16 is a time chart illustrating exemplary packet communication madein step S107.

In a case where an asynchronous command is present other than at asynchronous command transmission timing, only the asynchronous commandis transmitted in a packet as illustrated in FIG. 16. In a case where aplurality of asynchronous commands are present, the plurality ofasynchronous commands are multiplexed and transmitted in one packet. Thestate in which two asynchronous commands are in contact in FIG. 16indicates that the two asynchronous commands are transmitted in onepacket. An asynchronous command can be transmitted even at a timing notcorresponding to the cycle of the synchronous signal or the cycle of themultiplied synchronous signal.

On the other hand, in a case where it is determined in step S106 that anasynchronous command is not present, the lens control unit 22 terminatesthe processing. That is, in a case where it is determined in step S106that an asynchronous command is not present, neither a synchronouscommand nor an asynchronous command is transmitted and the processing isterminated.

The command transmission control processing is a processing oftransmitting a command from the lens control unit 22 to the body controlunit 72, but the command transmission control processing is performedalso when the body control unit 72 transmits a command to the lenscontrol unit 22.

As described above, in a case where the asynchronous commandtransmission timing matches with the synchronous command transmissiontiming, the body control unit 72 and the lens control unit 22 cantransmit an asynchronous command and a synchronous command in the samepacket.

For example, an asynchronous command indicating the speed information ofthe focus lenses and a synchronous command indicating the positioninformation of the focus lenses are multiplexed and stored in thecommand part in a packet, for example. The checksum for confirming thepresence of a communication error is calculated in units of packet andis stored in the footer. The checksum determination processing isperformed per packet, and thus an asynchronous command and a synchronouscommand are multiplexed and transmitted in one packet, thereby reducingthe checksum determination processing and contributing to a reduction inthe computation processing amount and the processing time on thereception side.

Further, an asynchronous command and a synchronous command aretransmitted in the same packet, thereby reducing the data communicationamount and efficiently exchanging data. Further, the fact contributes tolower power consumption.

As described above, the asynchronous command is used fora command tochange the F value to the target F value, a command to transmit thediaphragm driving end time, and a moving command (including data) tomove the focus lens. A command to transmit the diaphragm driving endtime is transmitted in an asynchronous command so that the body controlunit 72 can acquire the accurate diaphragm driving end time withoutdelay, thereby contributing to faster shooting.

The steps described in the flowcharts in the present specification maybe of course performed in time series in the described orders, may notnecessarily be processed in time series, and may be performed inparallel or at necessary timings such as on calling.

Embodiments of the present technology are not limited to the aboveembodiments, and can be variously changed without departing from thespirit of the present technology.

For example, a configuration in a combination of all or some of theabove embodiments may be employed.

Additionally, the effects described in the present specification aremerely exemplary and are not restrictive, and any effect other than theeffects described in the present specification may be obtained.

Additionally, the present technology can take the followingconfigurations.

(1) An interchangeable lens including:

a diaphragm;

a diaphragm driving unit configured to drive the diaphragm; and

a lens control unit configured to transmit diaphragm driving informationincluding stabilization time information of the diaphragm to a shootingapparatus when the diaphragm driving unit drives the diaphragm.

(2) The interchangeable lens according to (1),

in which the lens control unit transmits a diaphragm driving parameterincluding stabilization time information of the diaphragm as thediaphragm driving information to the shooting apparatus.

(3) The interchangeable lens according to (1),

in which the lens control unit transmits information indicating adriving end timing of the diaphragm as the diaphragm driving informationto the shooting apparatus before the diaphragm finishes being driven inresponse to a command to drive the diaphragm from the shootingapparatus.

(4) The interchangeable lens according to (1),

in which the lens control unit transmits information indicating adriving end timing of the diaphragm as the diaphragm driving informationto the shooting apparatus before or after the diaphragm starts beingdriven in response to a command to drive the diaphragm from the shootingapparatus.

(5) The interchangeable lens according to (3) or (4),

in which the lens control unit calculates a driving end timing of thediaphragm on the basis of a time including a driving time and astabilization time of the diaphragm driving unit.

(6) The interchangeable lens according to (4),

in which when transmitting information indicating a driving end timingof the diaphragm to the shooting apparatus before starting driving thediaphragm, the lens control unit calculates a driving end timing of thediaphragm including a waiting time until the diaphragm driving unitstarts driving the diaphragm.

(7) The interchangeable lens according to (4),

in which when transmitting information indicating a driving end timingof the diaphragm to the shooting apparatus after starting driving thediaphragm, the lens control unit calculates a driving end timing of thediaphragm excluding a time after the diaphragm driving unit startsdriving the diaphragm and until the information is transmitted to theshooting apparatus.

(8) The interchangeable lens according to any of (3) to (7),

in which the command is a command to change an F value to apredetermined target F value, and

the diaphragm driving unit drives the diaphragm to change a current Fvalue to the predetermined target F value.

(9) The interchangeable lens according to (3), further including:

a recording unit configured to store a convergence waveform in which theamount of light passing through the diaphragm converges on a targetlight amount value over time,

in which the lens control unit calculates a driving end timing of thediaphragm including a stabilization time of the diaphragm by use of theconvergence waveform.

(10) The interchangeable lens according to (8), further including:

a recording unit configured to record table data including astabilization time of the diaphragm depending on the current F value andthe target F value,

in which the lens control unit calculates a driving end timing of thediaphragm including the stabilization time by use of the table data.

(11) The interchangeable lens according to (10),

in which the recording unit stores the table data including thestabilization time measured by use of the interchangeable lens.

(12) The interchangeable lens according to (10) or (11),

in which the recording unit stores the table data per predeterminedcondition.

(13) The interchangeable lens according to (12), further including:

a temperature sensor configured to detect a temperature,

in which the recording unit stores the table data per temperature, and

the lens control unit calculates a driving end timing of the diaphragmincluding the stabilization time by use of the table data depending on adetected temperature.

(14) The interchangeable lens according to (12) or (13), furtherincluding:

a posture detection sensor configured to detect a posture of theinterchangeable lens,

in which the recording unit stores the table data per posture, and

the lens control unit calculates a driving end timing of the diaphragmincluding the stabilization time by use of the table data depending on adetected posture.

(15) The interchangeable lens according to any of (12) to (14),

in which the recording unit stores the table data per aged state of theinterchangeable lens, and

the lens control unit calculates a driving end timing of the diaphragmincluding the stabilization time by use of the table data depending onthe aged state.

(16) The interchangeable lens according to any of (3) to (15),

in which the lens control unit transmits information indicating thedriving end timing to the shooting apparatus in asynchronouscommunication.

(17) An interchangeable lens control method,

in which a lens control unit of an interchangeable lens including adiaphragm, a diaphragm driving unit configured to drive the diaphragm,and the lens control unit transmits diaphragm driving informationincluding stabilization time information of the diaphragm to a shootingapparatus when the diaphragm driving unit drives the diaphragm.

(18) A shooting apparatus including:

a body control unit configured to determine an exposure start timing onthe basis of diaphragm driving information including stabilization timeinformation of a diaphragm acquired from an interchangeable lens.

(19) A camera system including an interchangeable lens and a shootingapparatus on which the interchangeable lens is mounted,

in which the interchangeable lens includes:

a diaphragm;

a diaphragm driving unit configured to drive the diaphragm; and

a lens control unit configured to transmit diaphragm driving informationincluding stabilization time information of the diaphragm to theshooting apparatus when the diaphragm driving unit drives the diaphragm,and

the shooting apparatus includes:

a body control unit configured to determine an exposure start timing onthe basis of the diaphragm driving information.

(20) The camera system according to (19),

in which the body control unit determines an exposure start timing onthe basis of a diaphragm driving parameter including stabilization timeinformation of the diaphragm acquired as the diaphragm drivinginformation from the interchangeable lens.

REFERENCE SIGNS LIST

-   1 Camera system-   10 Interchangeable lens-   22 Lens control unit-   25 Diaphragm-   30 Recording unit-   32 Temperature sensor-   46 Diaphragm driving unit-   60 Shooting apparatus (body)-   72 Body control unit-   76 Imaging device

1. An interchangeable lens comprising: a diaphragm; a diaphragm driving unit configured to drive the diaphragm; and a lens control unit configured to transmit diaphragm driving information including stabilization time information of the diaphragm to a shooting apparatus when the diaphragm driving unit drives the diaphragm.
 2. The interchangeable lens according to claim 1, wherein the lens control unit transmits a diaphragm driving parameter including stabilization time information of the diaphragm as the diaphragm driving information to the shooting apparatus.
 3. The interchangeable lens according to claim 1, wherein the lens control unit transmits information indicating a driving end timing of the diaphragm as the diaphragm driving information to the shooting apparatus before the diaphragm finishes being driven in response to a command to drive the diaphragm from the shooting apparatus.
 4. The interchangeable lens according to claim 1, wherein the lens control unit transmits information indicating a driving end timing of the diaphragm as the diaphragm driving information to the shooting apparatus before or after the diaphragm starts being driven in response to a command to drive the diaphragm from the shooting apparatus.
 5. The interchangeable lens according to claim 3, wherein the lens control unit calculates a driving end timing of the diaphragm on the basis of a time including a driving time and a stabilization time of the diaphragm driving unit.
 6. The interchangeable lens according to claim 4, wherein when transmitting information indicating a driving end timing of the diaphragm to the shooting apparatus before starting driving the diaphragm, the lens control unit calculates a driving end timing of the diaphragm including a waiting time until the diaphragm driving unit starts driving the diaphragm.
 7. The interchangeable lens according to claim 4, wherein when transmitting information indicating a driving end timing of the diaphragm to the shooting apparatus after starting driving the diaphragm, the lens control unit calculates a driving end timing of the diaphragm excluding a time after the diaphragm driving unit starts driving the diaphragm and until the information is transmitted to the shooting apparatus.
 8. The interchangeable lens according to claim 3, wherein the command is a command to change an F value to a predetermined target F value, and the diaphragm driving unit drives the diaphragm to change a current F value to the predetermined target F value.
 9. The interchangeable lens according to claim 3, further comprising: a recording unit configured to store a convergence waveform in which an amount of light passing through the diaphragm converges on a target light amount value over time, wherein the lens control unit calculates a driving end timing of the diaphragm including a stabilization time of the diaphragm by use of the convergence waveform.
 10. The interchangeable lens according to claim 8, further comprising: a recording unit configured to record table data including a stabilization time of the diaphragm depending on the current F value and the target F value, wherein the lens control unit calculates a driving end timing of the diaphragm including the stabilization time by use of the table data.
 11. The interchangeable lens according to claim 10, wherein the recording unit stores the table data including the stabilization time measured by use of the interchangeable lens.
 12. The interchangeable lens according to claim 10, wherein the recording unit stores the table data per predetermined condition.
 13. The interchangeable lens according to claim 12, further comprising: a temperature sensor configured to detect a temperature, wherein the recording unit stores the table data per temperature, and the lens control unit calculates a driving end timing of the diaphragm including the stabilization time by use of the table data depending on a detected temperature.
 14. The interchangeable lens according to claim 12, further comprising: a posture detection sensor configured to detect a posture of the interchangeable lens, wherein the recording unit stores the table data per posture, and the lens control unit calculates a driving end timing of the diaphragm including the stabilization time by use of the table data depending on a detected posture.
 15. The interchangeable lens according to claim 12, wherein the recording unit stores the table data per aged state of the interchangeable lens, and the lens control unit calculates a driving end timing of the diaphragm including the stabilization time by use of the table data depending on the aged state.
 16. The interchangeable lens according to claim 3, wherein the lens control unit transmits information indicating the driving end timing to the shooting apparatus in asynchronous communication.
 17. An interchangeable lens control method, wherein a lens control unit of an interchangeable lens comprising a diaphragm, a diaphragm driving unit configured to drive the diaphragm, and the lens control unit transmits diaphragm driving information including stabilization time information of the diaphragm to a shooting apparatus when the diaphragm driving unit drives the diaphragm.
 18. A shooting apparatus comprising: a body control unit configured to determine an exposure start timing on the basis of diaphragm driving information including stabilization time information of a diaphragm acquired from an interchangeable lens.
 19. A camera system comprising an interchangeable lens and a shooting apparatus on which the interchangeable lens is mounted, wherein the interchangeable lens comprises: a diaphragm; a diaphragm driving unit configured to drive the diaphragm; and a lens control unit configured to transmit diaphragm driving information including stabilization time information of the diaphragm to the shooting apparatus when the diaphragm driving unit drives the diaphragm, and the shooting apparatus comprises: a body control unit configured to determine an exposure start timing on the basis of the diaphragm driving information.
 20. The camera system according to claim 19, wherein the body control unit determines an exposure start timing on the basis of a diaphragm driving parameter including stabilization time information of the diaphragm acquired as the diaphragm driving information from the interchangeable lens. 